The efficacy of pediatric elbow radiographic guidance in diagnosis of lateral humeral condyle fracture

Although lateral humeral condyle fracture is common, the incidence of missed diagnosis is very high. Delayed and missed diagnosis led to significant morbidities and loss of functions. We designed a pediatric elbow radiographic guidance aiming to improve the accuracy of diagnosis. This study was aimed to evaluate the efficacy of the radiographic guidance for the diagnosis of lateral condyle fracture. A cross-sectional study was conducted after defining the essential parameters as a guidance for assessing the pediatric elbow radiographs. We included medical students, emergency medicine, orthopedic, and radiology residents and fellows into this study. A questionnaire was used to evaluate the efficacy of the guidance. All participants underwent a pretest evaluation, followed by studying the guidance, and then finished a posttest evaluation. Baseline characteristics, diagnostic scores, and parameter evaluation scores were collected. The pretest and posttest scores were analyzed using paired t-test. Association between baseline characteristics and diagnostic scores were analyzed using multiple regression analysis. We included 177 participants. Average diagnostic score was significantly increased after using the guidance, from 12.2 ± 1.9 to 13.0 ± 1.7 (p < 0.0001). Medical students showed the most improvement, from 11.9 ± 1.9 to 13.1 ± 1.3 (p <0.001). All means of essential parameter evaluation scores were significantly improved in overall participants.The pediatric elbow radiographic guidance is useful for evaluation and diagnosis of lateral condyle fracture, especially for young physicians and trainees. Therefore, this should be recommended in routine medical education and general practice.


Introduction
Lateral condyle fracture is one of the most common elbow fractures in children [1][2][3][4].The incidence is 1.6 per 10,000 children per year, which accounts for 10-20% of pediatric elbow fractures [5,6].Even though lateral condyle fracture is very common, the diagnosis has been reported to be missed by clinicians.For instances, Shrader MW et al. reported that 60% of lateral condyle fracture were missed by general practitioners and emergency physicians [7].
Missed diagnosis of lateral condyle fracture can lead to non-union, malunion, limited range of motion, functional disturbance, varus/ valgus deformities and nerve palsy [5,6].Some of these consequences result in permanent deformities and morbidity [8].Therefore, accurate diagnosis and appropriate treatments are crucial for preventing the complications.To diagnose lateral condyle fracture, the physicians need to gather data from history taking, physical examination, and radiographic evaluation.Nevertheless, history taking and physical examination in young patients are challenging and sometime unreliable.Therefore, standard radiographs of the elbow are essential for the diagnosis [9].Evaluation of pediatric elbow radiographs is difficult especially for trainees and general practitioners.Many essential radiographic parameters include the posterior fat pad sign, anterior humeral line, radiocapitellar line, Baumann's angle, and fracture line at lateral condyle on both anterior-posterior (AP) and lateral radiographs.Moreover, the proper position of the elbow and quality of the radiographs are important [10][11][12][13][14].
According to data from the medical council of Thailand, there are only 2,500 orthopedic surgeons in the country taking care of more than 69 million population [15,16].The proportion of orthopedic surgeon per population is 1 per 27,600.Additionally, a large number of them are working only in big city areas.Therefore, the physicians who are early responsible for diagnosis of lateral condylar fracture are general practitioners due to limited numbers of orthopedic surgeon, but accurate diagnosis may be difficult and requires professional experiences.The authors initiated a radiographic guidance aiming to help the physicians to improve accuracy of diagnosis of lateral condyle fracture in children.
The purpose of this study was to evaluate the efficacy of the pediatric elbow radiographic guidance in diagnosis of lateral condyle fracture among inexperienced physicians and trainees, including medical students, emergency medicine residents, orthopedic residents and fellows and radiology residents and fellows.

Study design
A cross-sectional study was conducted after receiving approval from the Ethics Review Committee of Ramathibodi Hospital, affiliated with Mahidol University (ID 08-58-08).Each participant provided informed written consent before being included in the study.The study was conducted from September 2015 to September 2016.

Subject and methods
We recruited medical students who have already finished orthopedic rotation, emergency medicine residents, orthopedic residents and fellows and radiology residents and fellows.
The literature reviews together with referencing the standard textbooks was done to identify the essential radiographical parameters for the diagnosis of elbow fractures in children.We then developed a pediatric elbow radiographic guidance explaining the definitions, providing the examples of normal and abnormal radiographs for each essential parameter.The steps for evaluating the radiographs were orderly exhibited.Starting with the first step is to assess the quality of the radiographs in both AP and lateral views, then look for the obvious fracture.(Fig 1 ) If the fracture could not be clearly identified, the next step is to look for other five essential parameters to evaluate the radiographs including posterior fat pad sign, anterior humeral line, radiocapitellar line, fracture line in both AP and lateral views, and soft tissue swelling.A questionnaire was created for pre-test and post-test evaluations in order to assess the efficacy of the guidance.(Figs 6 and 7) The questionnaire consisted of 16 radiographs, including 5 normal cases, 2 supracondylar fractures, and 9 cases of lateral condyle fractures of various degrees.Details of radiographs such as patients' identification, serial numbers, data and time were blinded.All radiographs had been independently evaluated and confirmed for diagnosis by two experienced pediatric orthopedic surgeons.Each correct radiographic diagnosis was scored as 1 point, with a total possible score of 16 for the 16 radiographs.
After obtaining informed consent from the participants, we collected baseline characteristics, including age, gender, work experience, number of case experiences, orthopedic grade in medical school, and experience in orthopedic internship.Participants were then asked to evaluate the questionnaire and record their evaluations on pre-test answer sheets.Subsequently, each participant was provided with the pediatric elbow radiographic guidance for 10 minutes of self-study.After finishing the study, they were asked to evaluate the questionnaire containing 16 radiographs in different orders from pre-test, and answered in post-test answer sheet.Baseline characteristics of participants, their radiographic evaluations, and diagnosis for each case from both pre-test and post-test were collected.We collected data in each department and included all participants who were willing to participate the study.There was no responders because all participants answer the questionnaire at the same time in department meeting room.

Statistical analysis
The sample size was calculated based on a pilot study of each group.The alpha error was 0.05 and power of the study was 0.8.Mean difference of pre-test and post-test diagnostic scores and standard deviations were 2.6 ± 2.39, 1.0 ± 1.92, 1.0 ± 1.09, and 0.79 ± 1.44 in medical students, emergency medicine residents, orthopedic residents and fellows and radiology residents and fellows, respectively.Sample size calculation were 9 for medical students, 31 for emergency medicine residents, 11 for orthopedic residents and fellows and 28 for radiology residents and fellows.Pre-test and post-test parameter evaluation scores and diagnostic scores were analyzed using paired t-test.The association between baseline characteristics and diagnostic scores improvement was tested using multiple regression analysis.The statistical analysis was done using STATA 13.0 (StataCorp, College Station, Texas, USA).

Results
One hundred and seventy-seven participants were enrolled in this study.There were 60 of medical students, 32 of emergency medicine residents, 57 of orthopedic residents and fellows, and 28 radiology residents and fellows.Baseline characteristics were significantly different in each group which represent the divergence of each group.Baseline characteristics were presented in Table 1.
Means of parameter evaluation scores were significantly improved for all four parameters in overall participants.The mean of posterior fat pad sign evaluation scores was increased from 11.2 ± 2.0 to 12.1 ± 1.7 (p < 0.001).Mean of anterior humeral line evaluation scores were improved from 11.0 ± 2.4 to 12.2 ± 2.0 (p < 0.001).For the mean evaluation scores of fracture line increased from 12.8 ± 1.7 to 13.5 ± 1.2 (p<0.001) in AP view, and 13.6 ± 1.8 to 14.2 ± 1.5 (p< 0.001) in lateral view.Finally, the mean of soft tissue swelling improved from 12.0 ± 2.1 to 13.11 ± 1.8 (p< 0.001) as shown in Table 3.
The multiple regression analysis of association between baseline characteristics and diagnostic scores showed no association as shown in Table 4.However, the increasing of age and work experience tend to improve the diagnostic scores with the coefficient 0.25 (-0.66, 1.15), and 0.13 (-0.47, 0.72), respectively.

Discussion
Our findings demonstrated that pediatric elbow radiographic guidance significantly enhanced the ability to evaluate essential parameters and diagnose lateral condyle fractures.Although According to a previous study, the prevalence of missed diagnosis of lateral condyle fracture was as high as 60% [7].In our study, the rate of missed diagnosis was 23% before using the guidance.This may be due to the use of questionnaire for essential parameters evaluation with a specific answer format.The answer format might have potentially guided the participants to evaluate all mandatory parameters and lead to the correct diagnosis, and the missed diagnosis may have been underestimated.Moreover, the final diagnosis was in binary form (yes or no), and participant making a correct diagnosis by chance cannot be ruled out.The study questionnaire could be considered as a limitation of this study reflecting the use of a questionnaire did not resemble a real situation.
In spite of the influential effect of the questionnaire to influence the participants and lower the rate of missed diagnosis in pre-test evaluation, the guidance still showed significant improvement of the diagnostic scores with the missed diagnosis dropping to 16% at post-test compared with 23% at pre-test.Participants' diagnostic scores of fracture line (AP view and lateral view) in Jacob type I improved after the students and residents read the pediatric elbow Even after the use of guidance, fractures were still being missed by medical students, residents, and fellows.This points out that, for better diagnostic accuracy in lateral condyle fractures, professional exposure and experience may be more important than only nourishing with explicit knowledge in radiographic evaluation.In order to foster our young health professionals, real case-based teaching, coaching, mentoring and continuing practice should be emphasized in our medical education system.
According to previous literatures, many radiographic parameters are used for assessment of the pediatric elbow fractures, both in coronal and sagittal views.Poppelaars et al demonstrated that angle measurement of posterior fat pad has high inter and intra-observer reliability, with intraclass correlation coefficient of 0.95 (95% CI, 0.91-0.98)and 0.91 (95% CI, 0.41-0.99),respectively.In addition, the author recommended that the anterior fat pad of 16 degrees or more and any visible posterior fat pad are considered positive fat pad signs or abnormal and would help to identified the fractures [17].
Anterior humeral line is also beneficial for evaluation of elbow fractures.Abnormal anterior humeral line on lateral radiographs indicated displaced fractures.Yao B et al described that anterior humeral line has good intraclass correlation coefficient (0.81) only if it is measured on a non-rotated lateral radiograph.Therefore, the quality of the radiographs or the position of the patients during the x-ray processes are important [18].
Radiocapitellar line has been recommended as a radiographic parameter to evaluate the alignment between proximal radius and capitellum.However, using the radiocapitellar line in young children may have some limitation.Fader LM et al described that the radiocapitellar line does not reliably intersect the central third of capitellum in girls age less than 10 years and boys age less than 11 years due to the eccentric ossification center of capitellum [19].The strength of our study was the inclusion of various degrees of fracture severity as well as comparative levels of orthopedic knowledge and practical experience among participant groups.The limitations of this study included the fact that the study was conducted in one university hospital, therefore, the results may not be applicable to other tiers of hospitals.We only provided AP and lateral radiographs which are standard views in routine practice.However, the oblique radiographs are very important in diagnosing lateral condyle fractures.More studies should be conducting including oblique radiographs.If the oblique radiograph is found to be particularly useful in the diagnosis of lateral condyle fractures, then it should be introduced into routine practice as a standard radiographic view.This study was conducted in 2016 which was many years ago, so it may lag of some updated information.However, the pattern of lateral condyle fracture seems to be the same with unchanged classification during these years.Moreover, the questionnaire was radiographic based and with lack of clinical information, which may alter decision making.A multicentered study with clinical and radiographic information should be done in the future.

Conclusion
The pediatric elbow radiographic guidance, using PARFS steps, is beneficial for radiographic evaluation and diagnosis, especially for low experienced physicians and trainees.It should be recommended for use in routine medical education and general practice.However, more studies on the impact of pediatric elbow radiographic guidance on students and residents especially with the inclusion of oblique view radiographs will further provide assurances on the benefits of the guidance on the diagnosis of lateral condyle fractures.